import java.io.*;
import java.text.*;
class FileNameWithTimeStamp {
  //private static SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss.SSS"); // ."SSS" => milliseconds
  private static SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
  public static void main(String[] args) {
    try {
      // Atomically creates a new, empty file named by this abstract pathname
      // if and only if a file with this name does not yet exist.
      new File("C:\\"+sdf.format( System.currentTimeMillis() )+".txt").createNewFile();
    } catch(IOException x) { x.printStackTrace(); }
  }
}